The primary goal of this project is to evaluate an active synthetic analog of actinomycin D (AMD) with novel biochemical pharmacological properties. The analog is 7-(2, 3-epoxypropoxy)actinomycin D (rac-EPA), which shows superior antitumor activity in the P388, L1210, B16 and C26 tumors in mice to that of AMD. The analog shoes a high activity in a MDR tumor line in mice, e.g., P388/ADR which is cross resistant to AMD. Pure (90%) enatimeric forms of rac-EPA are R-(+)- and S(-)-EPA; both show high activity in the above tumor lines; we now propose to test these enantiomers in a more challenging and broader line of experimental tumors in mice. Accordingly, we will test these analog against i.v. implanted Lewis lung carcinoma and s.c. implanted C38 colon adenocarcinoma in B6C3F1 mice. We propose to test these active enantiomers in s.c. implanted MX-1 human mammary xenograft, and CX-1 human colon tumor xenograft transplanted in NIH(S)-nude mice following the reported and established procedures. Biochemical-pharmacological studies with isolated DNA and liver epoxide hydrolase and glutathione S-transferase enzymes have established that the enantiomers generate characteristic DNA-base adducts and enzyme induced end products. In this grant project, we propose to investigate the pharmacokinetic distribution of the enantiomers and biological adducts and conjugates in the bile, urine and tissues of Wistar rats in a time dependent study. The assay techniques will be primarily HPLC analysis of the DNA-base adducts in conjunction of Sephadex and other column chromatography. Labelled 14C- and 3H- enantiomers and their biotransformed products will be characterized with the aid of markers. The assay of those DNA-based adducts which need further refinement in sensitivity will be analyzed by post-labelling the HPLC fractions with gamma 32P-labelled ATP/polynucleotide kinase and 32P-labelled 3', 5'-biphosphates and the specific adducts will be analyzed by two-dimensional thin layer chromatography and identified by synthetic markers.